The field of the invention relates to devices for the extraction of oil from fruit.
There is currently an increasing world-wide demand for oils derived from the peels of citrus fruits. This is particularly so for lemon oil. Generally, these oils have been obtained by one or more mechanical operations performed on the rind or peel of the particular fruit. One particular type of device used to extract oils from whole fruit is disclosed in U.S. Pat. No. 4,070,959, incorporated by reference. This patent discloses an apparatus that utilizes a large number of horizontal parallel rollers. The rollers include thin metal rings having sharp teeth. During operation, whole fruit travels over the rollers and moves into and out of adjacent troughs between the rollers.
The trough region between adjacent rollers within a group of rollers, is generally referred to as the working region, since this is the area where the teeth of the rollers puncture the exterior surface of each whole fruit in a substantially uniform manner. The oils present within the cells in the peel or rind are released when pierced and agitated by the rollers.
As described in U.S. Pat. No. 4,070,959, the rollers are driven by a series of drive chains and sprockets. The horizontal rollers are arranged into groups or series. FIG. 2 of U.S. Pat. No. 4,070,959 shows rollers driven in groups of four. Individual drive chains engage the four adjacent rollers. While each roller within a group is driven in the same direction, the next adjacent roller rotates at a progressively lower rate. This speed differential produces penetration of the teeth into the rind or peel.
There is a disadvantage, however, when using groups of rollers to pierce the exterior surface of whole fruits. The pocket or trough formed between the last roller of one group and the first roller of the next group is what is referred to as a non-working pocket. This non-working pocket between the adjacent group of rollers results from the higher speed roller trying to pull the fruit out of the pocket faster than the slower roller is trying to pull it in. In a standard machine having forty rollers, when groups of four rolls are employed, there are 9 non-working pockets.
Attempts have been made to increase the efficiency of these types of machines by using groups of 8 rollers instead of four rollers. A standard 40 roller machine using groups of 8 rollers has only 4 non-working pockets.
Machines employing large numbers of rollers within a group, however, are undesirable in certain aspects. For example, it is often desirable to change the speed differential between adjacent rollers within a group as the condition of the fruit changes (i.e., ripe fruit vs. non-ripe fruit). This has been accomplished by mechanically adjusting the drive chains on alternate sprockets on the machine. While this operation can be performed relatively quickly in machines using groups of 4 rollers, the procedure and devices necessary for groups of 8 rollers are much more complex. It could take a mechanic several hours to make the needed changes in a machine having groups of 8 rollers. This creates costly downtime that reduces the overall throughput of the machine.
Thus, there is a need for an machine that increases the efficiency of oil extraction. In addition, there is a need for a machine that requires little or no downtime when adjustments are made to the rotational speeds of adjacent rollers. It is also desirable to have a machine that can form various groupings of rollers depending on the job requirement.